सूर्य के प्रकाश को सूर्य से पृथ्वी तक यात्रा करने में औसतन कितना समय लगता है?

The International Space Station operates in a low Earth orbit at an average altitude of approximately how many kilometers from the Earth's surface?

Generally, operational artificial satellites do not fly below which of the following altitudes (in km) due to atmospheric drag?